# All Questions

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### Difference between ACI Code and Eurocode in Stiffness modifiers?

According to the ACI Code stiffness modifiers (modifiers used to reduce the moment of inertia) are used for each structural elements for example 0.7 for columns and 0.35 for beams... For those who ...
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### Seismic Design Changes between ASCE and UBC Code?

what is the difference between the seismic design between ASCE and UBC code? from load combinations to loads applied to the history between the sudden shift or change in the code. and which one of the ...
20 views

### What is the Difference between ASCE and IBC Code?

What is the fundamental difference between the ASCE Code and IBC Code and what is the objective of each one? Thank you in Advance.
19 views

### Slab Stiffness Modifiers applied in Vertical Elements design but not in Slab design?

Why in the design of vertical elements (columns and walls) for a structure against lateral loads (such as seismic and wind) we use a slab (or shell) with a stiffness modifiers (such as 0.25 according ...
21 views

### Drop Panel Design Above Columns?

How to design a drop panel at a column in case the column above is rotated or not aligned to the below column (see image below), the code that i am using is the ACI Code if any reference for the ...
15 views

### how do cordless lawn mowers determine lawn density

Some cordless lawn mowers have a feature that causes the motor to cut off when the mower is rolled over a driveway or over a section of lawn where the grass is very sparse. How does the mower sense ...
19 views

### At what level is the Grade Beam most effective at pile cap level or at Slab-on-grade level?

The primary two functions of a Grade/Tie Beam in spread footing and/or pile caps foundation system is to support the Slab-On-Grade (S.O.G) and/or to take the moment from eccentric footing (or moment ...
15 views

### Difference between Allowable Bearing capacity Service and Ultimate?

When we calculate the dimension of a foundation we always use the allowable SERVICE bearing capacity (lets call it qs) and all the necessary checks are based on this value qs. My question is why does ...
27 views

### Most efficient turbine for harnessing energy from bidirectional air flow?

I am currently working on designing an oscillating water column as part of a project. In summary: OWC are devices with a semi-submerged chamber or hollow open to the sea below, keeping a trapped ...
16 views

### pmma vs glass windows? [closed]

I was told that PMMA is preferred over glass for windows in cold climates because of it's R-value being higher than glass.I wish there were a stick-on film made of glass! That could be used to cover ...
9 views

### How to connect to heating networks both with sources and consumers into one network?

We need to connect two distinct heating networks on a wastewater treatment plant into one. So far I've only seen heating networks with one central heat source or one central manifold that all heat ...
27 views

### Mechanical solution for keeping a vertical stack under pressure

I'm looking for a solution for keeping a vertical stack of small boxes under tension. I will use the device in the attached picture to hold the boxes which will have a lid on the top, and the boxes ...
58 views

### How to calculate required torque

Currently I'm doing a personal project, but I've some doubts about the calculation process. Well, I've a platform (2.30m length x 0.32m width). This platform is supported by 4 wheels with a diameter ...
25 views

### How can we recover/recycle Zinc by Blast Furnace Filter Dust? [closed]

The Blast furnace's filter dust generates/contains Zinc(Zn) material a lot. We are trying to find out how can we re evaluate this chemical inside of Iron & Steel works. I saw some research ...
32 views

### Can hydraulics be used with a squarish piston?

I'm designing a custom part that needs an active shock absorber and space is restricted. I most likely won't be able to use a stock absorber and was thinking, can two squarish tubes be made tight ...
4 views

### blockMesh fails with Foam::error::printStack

I am trying to generate a mesh using blockMesh. My blockMeshDict looks like this: ...
28 views

### Straight Pipe Thread

Is there any National Pipe Thread Straight (non-tapered, requires O-ring or compression olive) that is compatible, even loosely, with a machine thread threaded rod? I want to put a reducer on the end ...
18 views

### What engineering concepts are used in EV3 programming/ a Mindstorms robot? [closed]

If possible, could someone please compile a list of the engineering concepts associated with EV3 programming and Mindstorms robots. Thank you - your answers are much appreciated.
14 views

### Can a car's Electronic Stability Control (ESC) operate using electromagnetic braking?

The Wikipedia article for ESC describes the process as using hydraulic anti-lock brakes. However, is it possible for electromagnetic braking to be used instead, with an electic motor/generator in ...
35 views

### Any books about design of complex machines? [closed]

I'm familiar with several books that deal with the analysis and design of simple mechanisms (such as Norton's Design of Machinery), including four-bar linkages, gear trains and cams. There are also ...
17 views

### Can a “surface drive” propeller be submerged if induced supercavitation reduces water surface area?

Assuming induced supercavitation (like Supercavitating torpedo and Juliet Marine Systems Ghost) reduces water surface area does that reduce friction enough to submerge a surface drive propeller ...
14 views

### Submerged gate hydrostatics question

I know I must integrate this problem, but I am confused as to what exactly I supposed to integrate. Could you help me with the method for solving this problem? dF = rho * g * y
14 views

### When Convection exceeds radiation loss

A very hot small metal cylinder of mass, 50 g and surface area, 2 x 10^-3 m^2 , specific heat capacity, 500 J kg^-1 K^-1 and thermal conductivity, 25 W m^-1 K^-1 is to be rapidly cooled from 800°C and ...
30 views

### How can we evaluate industrial filter residue Sodium Sulphate? [on hold]

If an industrial sinter filter produces much more Na2SO4 (Sodium Sulphate) as residue, what can we do with it ? Can we re evaluate it inside of Iron & Steel plant? Or which importers can buy it? ...
23 views

### How does a nuclear powered rocket engine work?

Nuclear power always require some way of converting the energy from nuclear to electrical or mechanical to be useful. For example, in a nuclear power generation facility, this is done through heat/...
11 views

### Confusion about throttling process

A throttling process is defined as an isenthalpic process. But in certain cases, the throttling process is defined with the stagnation enthalpy being constant (ref: http://web.mit.edu/16.unified/www/...
29 views

### Aluminum tube vs steel

Our question is what size and alloy aluminum tube can be used to replace steel tube in a vertical load application. Our current spec is 1.5” OD STD steel tubing 7 feet long. We will use 6 poles ...
22 views

### Is there something called the stagnation volume?

When discussing the stagnation flow properties we always discuss stagnation temperature, stagnation pressure, and stagnation enthalpy. Is there also a stagnation property called the stagnation volume ...
21 views

### What is the smallest size of pipe to which I can Weld a 1 inch pipe Perpendicular to the Axis?

I would to know what is (or how to calculate) the size (dia) if the smallest pipe to which I can weld a 1 inch pipe from the side of the bigger pipe perpendicular to its axis (like a tee).
15 views

### Car's shock absorbers' damping ratio

I'm trying to find a suitable shock absorber for a small ATV with a specific value (to be determined later). But everywhere I look, no one seems to be giving the damping ratio of the shock absorbers. ...
18 views

### Efficiency of a fully-engaged friction clutch

I'm wondering whether there are any notable losses in a typical automobile clutch when fully engaged. Only losses that come to mind: material twisting with torque changes slipping due to imperfect ...
34 views

### Surface Area to Volume Ratio

I know there are some aspects we can try to apply this surface area to volume ratio to say physical chemistry in order to see reactivity of chemicals. However I am very confused in my structural ...
30 views

### What are the essentials of a good PRD (product requirements document) for a new mechanical device

I need to write a non technical product requirements document for a new machine that I want designed. I need to write a PRD, and I need to ensure that I have included all the salient information, ...
12 views

### In a throttling process do we consider static pressure or stagnation pressure and is there a reverse throttling process?

In a throttling process, the 'pressures' decreases whereas the enthalpy and so the 'temperature' remains constant. Are these pressures and temperatures static values or the stagnation values? I am ...
26 views

### Can temperature gradient keep concrete wall below 100% RH in 100% RH atmosphere?

Consider a high and wide concrete wall of say 30 cm thickness, covered with a sheet of vapor barrier on one side, and a sheet of say 30 cm thick and effective insulation on the other side. The vapor ...
29 views

### In an automatic transmission would it be better to have less shift elements applied in order to achieve gear ratio or more?

On ZF's website they stated that in their ZF8HP transmission they can achieve gear ratios with only 2 shift elements open which reduces drag losses. But what is bothering me is that drag loss isn't ...
21 views

### Memory management in for multiple cores of a processor

I come across a question-'How big an address space should I allocate for each ARM A53 core in a mobile processor?' What is the answer for this? Does it refer to memory management in SoC?
25 views

### Is there a relationship between depth/diameter/etc… of meteoric craters and the strength (eg:compressive strength) of the target material (sand…)?

So I am trying to write a high school research paper (3700 words) on the topic above. I am not sure if there is such a relationship, but I think intuitively we can agree that different materials will ...
11 views

### Pressure Change and Tractive Force between Two Plane Surfaces

just wondering if someone has any ideas, as to how I can solve this question. I am just a bit stumped as to where to start with this one. Question Two plane surfaces, one being fixed and the other ...
17 views

### Turbocharger boost control using two valves with a vac and boost reference for wide boost control range

Can someone explain how the above boost control setup would work. The valve on the left uses a vac source applied to the top of the diaphram which would effectively help hold the spring closed at high ...
35 views

### What wheel setup on a small, solar powered car, would have the least rolling friction?

We are attempting to design a solar car. The solar panel 4 1/2" x 13". I like to break these problems into their simplest form, in order to eliminate the least amount of possibilities. So, the goal ...
22 views

### What developments made diesel engines suitable for personal cars in the 1970s/1980s?

Both diesel and gasoline engines were developed in the late 19th to early 20th century. Diesel engines were for the most part of the 20th century used mostly for large applications in ships, trains, ...
35 views

### How do I find the vertical reaction forces?

The horizontal Force $A_x$ is easy but how did they get the vertical forces $A_y$ & $B_y$? I tried using similar triangles for the Force and length of the sides, somehow I can't manage to solve it....
10 views

### How to calculate a dynamic response from a transient response graph?

I have a transient graph as shown below and I need a dynamic response of the same. Probably we can calculate with the help of a transfer function if I am not wrong. if that is the case, how do I ...
20 views

### Power/energy density of an actuator

What is the meaning of power/energy density of an actuator? Context: As a novel kind of actuator, the dielectric elastomer ( DE ) demonstrates high-strain response [ 1 ] , high energy densities ( ...
75 views

### How to find Ship Longtitudinal Centre of Gravity

I did a Civil Engineering course some years ago and from my textbook I had a question on a ship. I found that a very interesting question, but unfortunately I haven't been able to find a solution to ...
23 views

### Problem regarding mathematical operators in concern with impulse

So, my Question is why do we have \begin{align} -S &= m_H (V_H' - V_H) \\ -S \cdot l &= \theta_B (w_B'-w_B) \end{align} because with what I understood about impulse so far, it should ...
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### k-value Rigid Pavements

Chapter 4, Part 3 of the MEPDG (Mechanistic Empirical Pavement Design Guide) states "The 'effective' dynamic k-value represents the compressibility of all pavement layers beneath the PCC slab and ...